There isn’t a way to do this with the built in coupon system. You could limit the coupons to 1 use per user under usage limits which gives you the ability to limit them somewhat but not completely to your needs.
What you might consider is using the Dynamic Pricing plugin and using roles to give certain users two levels of discounts, one as a percentage ( category, item or cart ) and the other as a dollar amount ( category, item or cart ). This would apply without the need of coupons and depend on user role.
https://www.woothemes.com/products/dynamic-pricing/
To get exactly what you want would require some custom coding to filter things that get entered into the coupon field, chec each and creating your own rules for applying them. You could still use the coupon system to build them but would have to have your own logic overriding the coupon field to control their use.